Electrical switches



Jan. 15, 1963 T. F. SMUSZ 3,073,935

ELECTRICAL SWITCHES 2 Sheets-Sheet 1 Filed April 11, 1961 Figl 22INVENTOR TEDDY E iMS BY MAJ Jan. 15, 1963 1'. F. SMUSZ ELECTRICALSWITCHES 2 Sheets-Sheet 2 Filed April 11, 1961 Fig.6

Fig.5

INVENTOR TEDDY F SMUSZ 7 Arron'm s Mm A atent 3,073,935 Patented Jan.15, 1963 Free 3,073,935 ELECTRICAL SWITCHES Teddy F. Smusz, Bristol,Conm, assignor to Royal McBee Corporation, a corporation of New YorkFiled Apr. 11, 1961, Ser. No. 102,165 3 Claims. (Cl. 200-460) Thisinvention relates to electrical switches; more particularly it relatesto push button switches characterized by wedge shaped contact elementsto achieve high contact pressures with minimum depressive forces.

It is an object of the invention to provide a reliable electrical keyingdevice.

Another object of the invention is in the provision of an electricalkeying device having a contact element operable to provide high contactpressure with a light depressive force.

Another object of the invention is in the provision of a reliableelectrical keying device 'of the push to make, release to break typeemploying a wedge type contact element.

A further object of the invention is in the provision of a reliableelectrical keying device of the make-break type employing a wedge typecontact element.

A still further object of the invention is to provide a reliableelectrical keying device employing a wedge type contact element whichisself adjusting to compensate for contact wear.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following fully depressed position of the switch;

FIGURE 4 is a side view of a push to make and break switch in its normalposition;

FIGURES 5, 6 and 7 are front views of the switch shown in FIGURE 4illustrating an intermediate position,

the make position and the position after a make respectively.

FIGURE 8 is an enlarged section view showing the contact mountingstructure of the FIGURE 4 contact element.

Referring now to the drawings there is shown in FIGURE 1 a rectangularbody 12 formed from insulating material having a peripheral flange 13and flexible detents 14 depending from the flange on opposite sides ofthe body. The body is provided with spaced slots 15 adapted to receivethe upper ends 16 of stationary contacts 17 as by a press fit. The bodyis also provided with a central slot 18 adapted to guide a plunger 19.The plunger is provided with a finger button 22 secured thereto as by apress fit, and is formed below the finger button with two shoulders 23and 24 respectively, the lower one of which is adapted in cooperationwith a central abutment 25 of the body to limit the downward movement ofthe plunger, and the upper one of which is adapted to maintain the upperend of a plunger return spring 26. The lower end of the spring 26 issupported by and insulated from the contact ends 16 extending throughthe body by an insulating washer 27 located and maintained by thecentral abutment.

As shown in FIGURE 1 the lower end 28 of the plunger is reduced in itswidth and extends freely through come shaped contact 36 a circuit ismade.

a contact element generally designated by reference numeral 32 which isurged toward a stop washer 33 at the lower extremity of the plunger by aspring 34 mounted about the plunger between the shoulder 35 formed bythe reduced width of the plunger and the contact element 32. The contactelement 32 comprises an inverted truncated cone 36 whose base diameteris greater than the spacing between stationary contacts 17; the latterbeing provided with rectangular cutouts 37 to permit movement of thecontact element 32 under the action of springs 26 and 34 as willhereinafter more clearly appear. Secured to the lower side of thecontact element is a truncated cone 38 of insulating material whose baseside is opposite that of the contact element. The base of the cone isformed with a flange 41 which in the normal position of the switch abutsthe lower edge 42 of the contacts 17. As shown in FIGURE 1 thestationary contacts 17 may be provided with tabs 43 to facilitate theconnection of leads whereby when the stationary contacts are bridged byth As illustrated most clearly in FIGURES 2 and 3 the lower edges 44 ofthe cutouts 37 in the stationary contacts 17 are bent outwardly therebyconforming to the angle of the cone shaped contact 36 to provide areliable contact area in the nature of a sliding or wiping contact andto minimize wear.

As heretofore stated FIGURE 1 shows the normal position of the switch inwhich spring 26 is only slightly compressed and spring 34 is relaxed.Depression of the plunger against the compressive force of spring 26exerts force on spring 34 which in turn transmits the force to thecontact element 32 whereby the plunger 19, spring 34, and contactelement 32 all move to the position shown in FIGURE 2 without anychanges in their relative positions; the compression of spring 34 beingnegligible. Upon further depression of the plunger the contact 36encounters the edges 44 presented by the stationary contacts 17, spring34 compresses thereby exerting force on the contact element which wedgesbetween the stationary contacts 17. The wedging effect producescomponents of force tending to spread the stationary contacts whichforces are greater than the downwardly exerted force of the plunger 19thereby giving a high contact pressure make. Upon release of the plunger19, spring 26 acts to return the parts to the positions shown in FIGURE1; the stop 33 carrying the contact element 32 upwardly and alsolimiting the upward motion of the plunger 19.

Referring now to FIGURES 4-8 there is shown a make-break or impulseswitch embodying the inventive concept. In this embodiment the cutouts37 in the stationary contacts 17 are enlarged in a vertical andhorizontal direction in order to provide supporting shoulders 51 for apermanent magnet assembly generally designated by reference numeral 52(see FIGURE 8) comprising rings 53 of insulating material tightlyembracing a disc shaped permanent magnet 54 for electrically isolatingthe permanent magnet from the stationary contacts 17. The magnet 54 isprovided with a central bore 55 through which the plunger 19 and aspring 34, corresponding to spring 34 of the FIGURE 1 embodiment, freelypass.

The movable contact element of this embodiment is also an invertedtruncated cone 56 and as shown in FIGURE 8 is coaxially mounted on andfor movement relative to a tubular sleeve 57 whose inside diameter islarge enough to permit the plunger 19 to move freely therein. The sleeve57 is provided with an outer annular shoulder 58 which fits into acavity 62 of larger diameter and coaxially of the bore of the contactelement 56 whereby when spring 34' urges the sleeve 57 downwardly upondepression of the plunger 19, contact element 56 will be urgeddownwardly. As shown in FIGURES 4-8 the lower extremities of thestationary contacts 17 are provided with openings 63 adapted to receiveas by a press fit laterally extending projections 64 of an insulatingmember 65 whereby they are maintained in parallel spaced relationship bythe insulating member. As shown in FIGURE 8 the insulating member 65 isprovided with a central boss 66 on its upper surface. The boss and theinsulating member are centrally bored; the latter only partly throughits thickness dimension. The opening thus formed in the insulatingmember guidingly receives the sleeve 57 and the bottom 67 thereof servesto limit its downward motion. A spring 68 is mounted about the sleeveand maintained coaxially of the sleeve by the outer surface of theinsulating boss 66; the upper end of the spring 68 abutting the lowersurface of the contact element, and the lower end abutting the uppersurface of the insulating member 65.

As heretofore stated FIGURE 4 shows the normal inoperative position ofthe switch wherein spring 26 is only slightly compressed, and springs 34and 68 are relaxed. FIGURE 5 shows the plunger 19 partly depressed withsprings 26 and 34 compressing. When the compressive force exerted byspring 34 on the sleeve exceeds the holding force exerted by thepermanent magnet 54 on the contact element 56 it will propel the sleeve57 and contact element 56 downwardly compressing spring 68. Since thecontact element is movable relative to the sleeve 5-7, when the latterbottoms in the insulating member the motion of the contact element 56will continue, further compressing spring 68 until the contact element56 bridges the edges 44 of the stationary contacts 17. This is theposition of the elements illustrated in FIGURE 6, the plunger alsohaving reached the limit of its downward movement. Immediately after thecontact element bridges the stationary contacts spring 68 forces thecontact element out of engagement with stationary contacts 17 to theposition shown in FIGURE 7, its upward motion being terminated by theannular shoulder 58 of the sleeve 57. Upon release of the plunger 19spring 26 returns it to normal and spring 68 drives the contact element56 and sleeve 57 upwardly into the zone of influence of the magnet 54whereupon magnetic force returns the contact element and sleeve to thenormal position of FIGURE 4; the return movement of the plunger removingthe influence of spring 34 on the sleeve 57 to permit its upward motionunder the influence of the magnet.

It should be understood that the foregoing disclosure relates to only apreferred embodiment of the invention and that it is intended to coverall changes and modifications of the example of the invention hereinchosen for the purposes of the disclosure which do not constitutedepartures from the spirit and scope of the invention.

The invention claimed is: i

1. An electrical impulse switch comprising an insulating support, spacedcontacts secured to said support, a plunger mounted for movementrelative to said support and between said spaced contacts, an invertedtruncated cone shaped contact element movable relative to and guided bysaid plunger, a spring mounted on said plunger for transmitting themotion of said plunger to said movable contact element, a permanentmagnet for releasably holding said movable contact element, saidmagnetic holding force opposing the compressive force stored in saidspring during an initial depression of said plunger, said magnetic meansreleasing said movable contact when said compressive force resultingfrom further depression of said plunger exceeds said magnetic forcewhereby said compressive force propels said movable contact elementbetween said spaced contacts, and spring means compressible by saidpropelled contact element for driving said contact element out ofengagement with said spaced contacts immediately after engagementtherewith and while said plunger is fully depressed.

2. An electrical impulse switch comprising an insulating support, spacedcontacts secured to said support, a plunger mounted for movementrelative to and between said spaced contacts, a magnet insulatedlysecured between said spaced contacts, an inverted truncated cone shapedcontact movable relative to and guided by said plunger, said magnetreleasably holding said cone shaped contact against movement, a springsecured to said plunger and bearing on said cone shaped contact adaptedto transmit the motion of said plunger to said cone shaped contact,means for depressing said plunger, said magnet restraining movement ofsaid contact by said spring until the energy stored thereby duringdepression of said plunger overcomes said restraining force and propelssaid contact between said spaced contacts, a second spring, said drivencontact compressing said second spring whereby the compressive forcestored therein immediately breaks contact between said cone shaped andsaid spaced contacts while said plunger is fully depressed, said secondspring returning said cone shaped contact into holding contact with saidmagnet upon return of said plunger to normal position.

3. A momentary contact switch comprising an insulating support, spacedcontacts secured to said support adapted to be momentarily bridged, aplunger mounted for movement relative to said support and between saidspaced contacts, said plunger being positionable from a normal to afully depressed condition, a contact element movable relative to saidplunger and adapted to momentarily bridge said spaced contacts, a motiontransmitting spring mounted on said plunger for transmitting the motionof said plunger to said contact element, permanent magnet means securedto said spaced contacts for releasably holding said contact elementuntil the force stored in said spring overcomes said magnet holdingforce and propels said contact element into contact with said spacedcontacts, and second spring means mounted on said plunger interposed inthe path of said propelled contact element whereby the energy storedtherein is operative in opposition to the force of said motiontransmitting spring to immediately break contact between said contactelement and spaced contacts while said plunger is in its fully depressedcondition, said second spring restoring said contact element intoholding contact with said magnet upon return of said plunger to normalposition.

References Cited in the file of this patent UNITED STATES PATENTS983,976 Carpenter Feb. 14, 1911 1,861,400 Miller May 31, 1932 2,605,375Ellithorpe July 29, 1952

1. AN ELECTRICAL IMPULSE SWITCH COMPRISING AN INSULATING SUPPORT, SPACEDCONTACTS SECURED TO SAID SUPPORT, A PLUNGER MOUNTED FOR MOVEMENTRELATIVE TO SAID SUPPORT AND BETWEEN SAID SPACED CONTACTS, AN INVERTEDTRUNCATED CONE SHAPED CONTACT ELEMENT, MOVABLE RELATIVE TO AND GUIDED BYSAID PLUNGER, A SPRING MOUNTED ON SAID PLUNGER FOR TRANSMITTING THEMOTION OF SAID PLUNGER TO SAID MOVABLE CONTACT ELEMENT, A PERMANENTMAGNET FOR RELEASABLY HOLDING SAID MOVABLE CONTACT ELEMENT, SAIDMAGNETIC HOLDING FORCE OPPOSING THE COMPRESSIVE FORCE STORED IN SAIDSPRING DURING AN INITIAL DEPRESSION OF SAID PLUNGER, SAID MAGNETIC MEANSRELEASING SAID MOVABLE CONTACT WHEN SAID COMPRESSIVE FORCE RESULTINGFROM FURTHER DEPRESSION OF SAID PLUNGER EXCEEDS SAID MAGNETIC FORCEWHEREBY SAID COMPRESSIVE FORCE PROPELS SAID MOVABLE CONTACT ELEMENTBETWEEN SAID SPACED CONTACTS, AND SPRING MEANS COMPRESSIBLE BY SAIDPROPELLED CONTACT ELEMENT FOR DRIVING SAID CONTACT ELEMENT OUT OFENGAGEMENT WITH SAID SPACED CONTACTS IMMEDIATELY AFTER ENGAGEMENTTHEREWITH AND WHILE SAID PLUNGER IS FULLY DEPRESSED.